A neighboring cell processing device includes: a measurement information acquisition unit 11 for acquiring measurement information which indicates a result of measurement of radio signals transmitted from a plurality of wireless base station devices other than a target wireless base station device, based on information provided from at least either of wireless terminal devices or wireless base station devices; and a neighboring cell information generation unit 12 for generating, based on the measurement information acquired by the measurement information acquisition unit 11, neighboring cell information which indicates one or a plurality of wireless base station devices located in the neighborhood of the target wireless base station device, among the plurality of wireless base station devices other than the target wireless base station device.Related Terms:Base StationData StructureWirelessProcessing DeviceRadio SignalTerminal Device

BACKGROUND ART

Background Art 1

In conventional mobile communication systems, communication services have been provided by wireless base station devices (hereinafter also referred to as macro base stations) each forming a cell having a radius ranging from several hundreds of meters to several tens of kilometers, i.e., an area in which wireless terminal devices are allowed to communicate with the wireless base station device.

In recent years, with a dramatic increase in the number of subscribers of mobile communication services and an increase in communication traffic due to data communication, it is desired to distribute the subscribers and the communication traffic over cells of smaller radii, and to reliably provide the users with a certain level of communication speed. Further, as a countermeasure against dead zones caused by skyscrapers, it is desired to install wireless base station devices in office floors and ordinary households.

In association with these requirements, downsizing of wireless base station devices has progressed due to remarkable improvement in throughput of various devices used in the wireless base station devices, and downsized base stations have attracted attention.

Such small-size base stations (hereinafter also referred to as “femto base stations”) form femto cells. Since the radius of each femto cell is as small as about 10 meters, it is considered that the femto base stations are used in places, such as homes and underground malls, which are outside macro cells foamed by macro base stations and where it is difficult to install macro base stations.

Further, since a large number of femto base stations are installed in a specific area, it is difficult to connect the femto base stations directly to a core network. Therefore, it is considered that a large number of femto base stations installed in a specific area are connected to a gateway device such as a HeNB-GW, and then the femto base stations are connected to the core network via the HeNB-GW.

In the above configuration, when installing femto base stations, if configuration of each femto base station is performed by a telecommunication carrier or a purchaser of the femto base station, considerable labor and cost are required. Further, every time a new femto base station is installed and thereby the number of femto base stations increases, not only configuration of the newly installed femto base station but also reconfiguration of already-installed neighboring femto base stations need to be performed.

In order to solve the above problems, for example, Patent Literature 1 disclosed technique as follows. That is, a new cell measures signal intensities of different channels used by already-existing cells. Then, the new cell forms a list of candidate channels corresponding to channels having relatively high signal intensities, and transmits this list to a mobile switching center of a cellular network. The mobile switching center determines which candidate channels correspond to beacons used in the existing cells, and transmits, to the new cell, configuration information relating to the existing cells. Then, the new cell automatically receives the configuration information relating to the neighboring cells. If the mobile switching center determines that none of the identified neighbors (neighboring cells) reaches a maximum value N, the mobile switching center requests the new cell to transmit an additional candidate channel (i.e., a candidate channel having a lower signal intensity).

Background Art 2

In conventional mobile communication systems, communication services have been provided by wireless base station devices (hereinafter also referred to as macro base stations) each forming a cell having a radius ranging from several hundreds of meters to several tens of kilometers, i.e., an area in which wireless terminal devices are allowed to communicate with the wireless base station device.

In recent years, with a dramatic increase in the number of subscribers of mobile communication services and an increase in communication traffic due to data communication, it is desired to distribute the subscribers and the communication traffic over cells of smaller radii, and to reliably provide the users with a certain level of communication speed. Further, as a countermeasure against dead zones caused by skyscrapers, it is desired to install wireless base station devices in office floors and ordinary households.

In association with these requirements, downsizing of wireless base station devices has progressed due to remarkable improvement in throughput of various devices used in the wireless base station devices, and downsized base stations have attracted attention.

Such small base stations (hereinafter also referred to as “femto base stations”) form femto cells. Since the radius of each femto cell is as small as about 10 meters, it is considered that the femto base stations are used in places, such as homes and underground malls, which are outside macro cells formed by macro base stations and where it is difficult to install macro base stations.

Further, since a large number of femto base stations are installed in a specific area, it is difficult to connect the femto base stations directly to a core network. Therefore, it is considered that a large number of femto base stations installed in a specific area are connected to a gateway device such as a HeNB-GW, and then the femto base stations are connected to the core network via the HeNB-GW.

In the above configuration, when installing femto base stations, if configuration of each femto base station is performed by a telecommunication carrier or a purchaser of the femto base station, considerable labor and cost are required. Further, every time a new femto base station is installed and thereby the number of femto base stations increases, not only configuration of the newly installed femto base station but also reconfiguration of already-installed neighboring femto base stations need to be performed.

In order to solve the above problems, for example, Patent Literature 1 discloses a technique as follows. That is, a new cell measures signal intensities of different channels used by already-existing cells. Then, the new cell forms a list of candidate channels corresponding to channels having relatively high signal intensities, and transmits this list to a mobile switching center of a cellular network. The mobile switching center determines which candidate channels correspond to beacons used in the existing cells, and transmits, to the new cell, configuration information relating to the existing cells. Then, the new cell automatically receives the configuration information relating to the neighboring cells. If the mobile switching center determines that none of the identified neighbors (neighboring cells) reaches a maximum value N, the mobile switching center requests the new cell to transmit an additional candidate channel (i.e., a candidate channel having a lower signal intensity).

Background Art 3

In conventional mobile communication systems, communication services have been provided by wireless base station devices (hereinafter also referred to as macro base stations) each forming a cell having a radius ranging from several hundreds of meters to several tens of kilometers, i.e., an area in which wireless terminal devices are allowed to communicate with the wireless base station device.

In recent years, with a dramatic increase in the number of subscribers of mobile communication services and an increase in communication traffic due to data communication, it is desired to distribute the subscribers and the communication traffic over cells of smaller radii, and to reliably provide the users with a certain level of communication speed. Further, as a countermeasure against dead zones caused by skyscrapers, it is desired to install wireless base station devices in office floors and ordinary households.

In association with these requirements, downsizing of wireless base station devices has progressed due to remarkable improvement in throughput of various devices used in the wireless base station devices, and downsized base stations have attracted attention.

Such small base stations (hereinafter also referred to as “femto base stations”) form femto cells. Since the radius of each femto cell is as small as about 10 meters, it is considered that the femto base stations are used in places, such as homes and underground malls, which are outside macro cells formed by macro base stations and where it is difficult to install macro base stations.

Further, since a large number of femto base stations are installed in a specific area, it is difficult to connect the femto base stations directly to a core network. Therefore, it is considered that a large number of femto base stations installed in a specific area are connected to a gateway device such as a HeNB-GW, and then the femto base stations are connected to the core network via the HeNB-GW.

In the above configuration, when installing femto base stations, if configuration of each femto base station is performed by a telecommunication carrier or a purchaser of the femto base station, considerable labor and cost are required. Further, every time a new femto base station is installed and thereby the number of femto base stations increases, not only configuration of the newly installed femto base station but also reconfiguration of already-installed neighboring femto base stations need to be performed.

In order to solve the above problems, for example, Patent Literature 1 discloses a technique as follows. That is, a new cell measures signal intensities of different channels used by already-existing cells. Then, the new cell forms a list of candidate channels corresponding to channels having relatively high signal intensities, and transmits this list to a mobile switching center of a cellular network. The mobile switching center determines which candidate channels correspond to beacons used in the existing cells, and transmits, to the new cell, configuration information relating to the existing cells. Then, the new cell automatically receives the configuration information relating to the neighboring cells. If the mobile switching center determines that none of the identified neighbors (neighboring cells) reaches a maximum value N, the mobile switching center requests the new cell to transmit an additional candidate channel (i.e., a candidate channel having a lower signal intensity).

Background Art 4

In conventional mobile communication systems, communication services have been provided by wireless base station devices (hereinafter also referred to as macro base stations) each forming a cell having a radius ranging from several hundreds of meters to several tens of kilometers, i.e., an area in which wireless terminal devices are allowed to communicate with the wireless base station device.

In recent years, with a dramatic increase in the number of subscribers of mobile communication services and an increase in communication traffic due to data communication, it is desired to distribute the subscribers and the communication traffic over cells of smaller radii, and to reliably provide the users with a certain level of communication speed. Further, as a countermeasure against dead zones caused by skyscrapers, it is desired to install wireless base station devices in office floors and ordinary households.

In association with these requirements, downsizing of wireless base station devices has progressed due to remarkable improvement in throughput of various devices used in the wireless base station devices, and downsized base stations have attracted attention.

Such small base stations (hereinafter also referred to as “femto base stations”) form femto cells. Since the radius of each femto cell is as small as about 10 meters, it is considered that the femto base stations are used in places, such as homes and underground malls, which are outside macro cells formed by macro base stations and where it is difficult to install macro base stations.

Further, since a large number of femto base stations are installed in a specific area, it is difficult to connect the femto base stations directly to a core network. Therefore, it is considered that a large number of femto base stations installed in a specific area are connected to a gateway device such as a HeNB-GW, and then the femto base stations are connected to the core network via the HeNB-GW.

In the above configuration, when installing femto base stations, if configuration of each femto base station is performed by a telecommunication carrier or a purchaser of the femto base station, considerable labor and cost are required. Further, every time a new femto base station is installed and thereby the number of femto base stations increases, not only configuration of the newly installed femto base station but also reconfiguration of already-installed neighboring femto base stations need to be performed.

In order to solve the above problems, for example, Patent Literature 1 discloses a technique as follows. That is, a new cell measures signal intensities of different channels used by already-existing cells. Then, the new cell forms a list of candidate channels corresponding to channels having relatively high signal intensities, and transmits this list to a mobile switching center of a cellular network. The mobile switching center determines which candidate channels correspond to beacons used in the existing cells, and transmits, to the new cell, configuration information relating to the existing cells. Then, the new cell automatically receives the configuration information relating to the neighboring cells. If the mobile switching center determines that none of the identified neighbors (neighboring cells) reaches a maximum value N, the mobile switching center requests the new cell to transmit an additional candidate channel (i.e., a candidate channel having a lower signal intensity).

Background Art 5

In conventional mobile communication systems, communication services have been provided by wireless base station devices (hereinafter also referred to as macro base stations) each forming a cell having a radius ranging from several hundreds of meters to several tens of kilometers, i.e., an area in which wireless terminal devices are allowed to communicate with the wireless base station device.

In recent years, with a dramatic increase in the number of subscribers of mobile communication services and an increase in communication traffic due to data communication, it is desired to distribute the subscribers and the communication traffic over cells of smaller radii, and to reliably provide the users with a certain level of communication speed. Further, as a countermeasure against dead zones caused by skyscrapers, it is desired to install wireless base station devices in office floors and ordinary households.

In association with these requirements, downsizing of wireless base station devices has progressed due to remarkable improvement in throughput of various devices used in the wireless base station devices, and downsized base stations have attracted attention.

Such small base stations (hereinafter also referred to as “femto base stations”) form femto cells. Since the radius of each femto cell is as small as about 10 meters, it is considered that the femto base stations are used in places, such as homes and underground malls, which are outside macro cells formed by macro base stations and where it is difficult to install macro base stations.

Further, since a large number of femto base stations are installed in a specific area, it is difficult to connect the femto base stations directly to a core network. Therefore, it is considered that a large number of femto base stations installed in a specific area are connected to a gateway device such as a HeNB-GW, and then the femto base stations are connected to the core network via the HeNB-GW.

In the above configuration, when installing femto base stations, if configuration of each femto base station is performed by a telecommunication carrier or a purchaser of the femto base station, considerable labor and cost are required. Further, every time a new femto base station is installed and thereby the number of femto base stations increases, not only configuration of the newly installed femto base station but also reconfiguration of already-installed neighboring femto base stations need to be performed.

In order to solve the above problems, for example, Patent Literature 1 discloses a technique as follows. That is, a new cell measures signal intensities of different channels used by already-existing cells. Then, the new cell forms a list of candidate channels corresponding to channels having relatively high signal intensities, and transmits this list to a mobile switching center of a cellular network. The mobile switching center determines which candidate channels correspond to beacons used in the existing cells, and transmits, to the new cell, configuration information relating to the existing cells. Then, the new cell automatically receives the configuration information relating to the neighboring cells. If the mobile switching center determines that none of the identified neighbors (neighboring cells) reaches a maximum value N, the mobile switching center requests the new cell to transmit an additional candidate channel (i.e., a candidate channel having a lower signal intensity).

CITATION LIST
Patent Literature

[PTL 1] Japanese Laid-Open Patent Publication No. 11-331931

SUMMARY

OF THE INVENTION

Problems to be Solved by the Invention

<Problem 1>

Regarding <Background Art 1>, purchasers of femto base stations are allowed to independently determine where to install the femto base stations. Therefore, in a wireless communication system in which femto base stations are installed, the femto base stations are likely to be moved or powered on/off. For this reason, it is difficult for a wireless base station device around which femto base stations exist to generate appropriate neighboring cell information.

For example, based on the neighboring cell information, a wireless terminal device measures the reception powers from femto base stations registered in the neighboring cell information, autonomously or according to an indication from a femto base station, and notifies the femto base station of the result of the measurement. In this case, if a femto base station that is not suitable as a handover destination is registered in the neighboring cell information, the wireless terminal device performs an unnecessary measurement operation, and unnecessary handover occurs.

The present invention is made to solve the above Problem 1, and an object of the present invention is to provide a neighboring cell processing device, a wireless base station device, and a neighboring cell processing method, which allow generation of appropriate neighboring cell information, and thereby realize efficient operation in a wireless communication system.

<Problem 2>

Regarding <Background Art 2>, purchasers of femto base stations are allowed to independently determine where to install the femto base stations. Therefore, in a wireless communication system in which femto base stations are installed, the femto base stations are likely to be moved or powered on/off. For this reason, it is difficult for a wireless base station device around which femto base stations exist to generate appropriate neighboring cell information.

For example, based on the neighboring cell information, a wireless terminal device measures the reception powers from femto base stations registered in the neighboring cell information, autonomously or according to an indication from a femto base station, and notifies the femto base station of the result of the measurement. In this case, if a femto base station that is not suitable as a handover destination is registered in the neighboring cell information, the wireless terminal device performs an unnecessary measurement operation, and unnecessary handover occurs.

The present invention is made to solve the above Problem 2, and an object of the present invention is to provide a neighboring cell processing device, a wireless base station device, and a neighboring cell processing method, which allow generation of appropriate neighboring cell information, and thereby realize efficient operation in a wireless communication system.

<Problem 3>

Regarding <Background Art 3>, purchasers of femto base stations are allowed to independently determine where to install the femto base stations. Therefore, in a wireless communication system in which femto base stations are installed, the femto base stations are likely to be moved or powered on/off. For this reason, it is difficult for a wireless base station device around which femto base stations exist to generate appropriate neighboring cell information.

For example, based on the neighboring cell information, a wireless terminal device measures the reception powers from femto base stations registered in the neighboring cell information, autonomously or according to an indication from a femto base station, and notifies the femto base station of the result of the measurement. In this case, if a femto base station that is not suitable as a handover destination is registered in the neighboring cell information, the wireless terminal device performs an unnecessary measurement operation, and unnecessary handover occurs.

The present invention is made to solve the above Problem 3, and an object of the present invention is to provide a neighboring cell processing device, a wireless base station device, and a neighboring cell processing method, which allow generation of appropriate neighboring cell information, and thereby realize efficient operation in a wireless communication system.

<Problem 4>

Regarding <Background Art 4>, in the mobile communication system, for example, based on neighboring cell information in which one or a plurality of wireless base station devices are registered, a wireless terminal device measures the reception powers of radio signals transmitted from the wireless base station devices registered in the neighboring cell information, autonomously or according to an indication from a wireless base station device, and notifies the wireless base station device of the measurement result. In this case, if a wireless base station device that is not suitable as a handover destination is registered in the neighboring cell information, the wireless terminal device performs an unnecessary measurement operation, and unnecessary handover occurs.

The present invention is made to solve the above Problem 4, and an object of the present invention is to provide a neighboring cell processing device, a wireless base station device, and a neighboring cell processing method, which allow generation of appropriate neighboring cell information, and thereby realize efficient operation in a wireless communication system.

<Problem 5>

Regarding <Background Art 5>, a femto base station operates in any of open, hybrid, and closed access modes, for example. When the femto base station operates in the closed access mode, only registered members (terminals) are allowed to access the femto base station. When the femto base station operates in the closed access mode, the femto base station provides services to only the registered members. When the femto base station operates in the hybrid mode, the femto base station provides services to both the registered members and unregistered members (non-members). When the femto base station operates in the open access mode, the femto base station operates in the same manner as a macro base station.

Meanwhile, purchasers of femto base stations are allowed to independently determine where to install the femto base stations. Therefore, in a wireless communication system in which femto base stations are installed, the femto base stations are likely to be moved or powered on/off. For this reason, it is difficult for a wireless base station device around which femto base stations exist to generate appropriate neighboring cell information.

For example, based on the neighboring cell information, a wireless terminal device measures the reception powers from femto base stations registered in the neighboring cell information, autonomously or according to an indication from a femto base station, and notifies the femto base station of the result of the measurement. In this case, if a femto base station which is not suitable as a handover destination, such as a femto base station in the closed access mode in which the wireless terminal device is not registered, or a femto base station which is powered off, is registered in the neighboring cell information, the wireless terminal device performs an unnecessary measurement operation, and unnecessary handover occurs.

The present invention is made to solve the above Problem 5, and an object of the present invention is to provide a neighboring cell processing device, a wireless base station device, a neighboring cell processing method, and a data structure, which allow generation of appropriate neighboring cell information, and thereby realize efficient operation in a wireless communication system.

Solution to the Problems

(1-1) In order to solve the above problem 1, the present invention relates to a neighboring cell processing device in a communication system in which wireless terminal devices are communicable with a plurality of wireless base station devices by performing movement operation, and the neighboring cell processing device includes: a movement information acquisition unit for acquiring movement information indicating a movement operation history of the wireless terminal devices, based on information from at least either of the wireless terminal devices or the wireless base station devices; a neighboring cell information generation unit for generating, based on the movement info, nation acquired by the movement information acquisition unit, neighboring cell information indicating one or a plurality of wireless base station devices located in the neighborhood of a target wireless base station device, among a plurality of wireless base station devices other than the target wireless base station device; and a neighboring cell information transmission unit for transmitting the neighboring cell information generated by the neighboring cell information generation unit, to the target wireless base station device or to wireless terminal devices communicable with the target wireless base station device.

This configuration allows automatic optimization of neighboring cell information regardless of movement and power on/off of each wireless base station device. Therefore, the efficiency of operation in the wireless communication system can be improved without manpower assistance. Further, since the neighboring cell information is automatically optimized, a special installation process for each wireless base station device is not needed, thereby reducing the time and cost required for installing the wireless base station device.

Accordingly, the efficiency of operation in the wireless communication system can be improved by generating appropriate neighboring cell information.

The “movement” of a wireless terminal device in the present invention includes not only handover which is an inter-base-station movement (inter-cell movement) operation performed by a wireless terminal device communicating with a wireless base station device but also an inter-base-station movement (inter-cell movement) operation performed by a wireless terminal device in the idle state.

(1-2) Preferably, the neighboring cell information generation unit ranks the plurality of wireless base station devices other than the target wireless base station device, based on the movement information acquired by the movement information acquisition unit, and generates neighboring cell information based on a result of the ranking.

This configuration allows generation of detailed neighboring cell information, and achieves further improvement in the efficiency of operation in the wireless communication system. For example, by preferentially selecting, as a destination of movement, a higher-rank wireless base station device in the ranking, the success rate of the movement operation can be increased.

In this configuration, for example, when the number of wireless base station devices that can be included in the neighboring cell information to be notified to the wireless terminal devices is limited, it is possible to notify the wireless terminal devices of appropriate neighboring cell information by including N wireless base station devices in the neighboring cell information.

(1-4) More preferably, the neighboring cell information generation unit generates neighboring cell information which further indicates the ranking of the ranked wireless base station devices.

This configuration allows generation of more detailed neighboring cell information, and achieves further improvement in the efficiency of operation in the wireless communication system. For example, based on the ranking of the wireless base station devices in the neighboring cell information, a wireless base station device performs determination of measurement order, selection of wireless base station devices as measurement targets, and the like, thereby realizing efficient measurement operation.

(1-5) Preferably, the neighboring cell information generation unit generates neighboring cell information which indicates one or a plurality of wireless base station devices to be candidate(s) for a destination of movement of a wireless terminal device communicating with the target wireless base station device, among the plurality of wireless base station devices other than the target wireless base station device.

This configuration causes the movement operation in a cell of an installed wireless base station device to be in the optimum state. Further, by performing optimization of the neighboring cell information, the number of neighboring cells to be candidates for a destination of movement of a wireless terminal device during communication can be reduced, thereby avoiding occurrence of unnecessary movement operation.

(1-6) Preferably, the neighboring cell information generation unit generates neighboring cell information which indicates one or a plurality of wireless base station devices to be target(s) of measurement by the wireless terminal devices, among the plurality of wireless base station devices other than the target wireless base station device.

In this way, by performing optimization of the neighboring cell information, the number of neighboring cells to be the targets of measurement by the wireless terminal devices can be reduced, thereby preventing the wireless terminal devices from performing unnecessary measurement operations.

(1-7) Preferably, the neighboring cell information generation unit generates neighboring cell information which indicates one or a plurality of wireless base station devices which transmit radio signal(s) whose reception level(s) are to be measured by the wireless terminal devices, among the plurality of wireless base station devices other than the wireless base station device.

In this way, by performing optimization of the neighboring cell information, the number of neighboring cells to be the targets of reception level measurement by the wireless terminal devices can be reduced, thereby preventing the wireless terminal devices from performing unnecessary measurement operations.

(1-8) More preferably, the neighboring cell information generation unit generates neighboring cell information which indicates one or a plurality of wireless base station devices which transmit radio signal(s) whose reception level(s) are to be measured by a wireless terminal device not communicating with the target wireless base station device, among the plurality of wireless base station devices other than the target wireless base station device.

This configuration reduces the number of neighboring cells to be the targets of periodical power measurement instructed by broadcast information or the like from a wireless base station device, thereby preventing each wireless terminal device from performing unnecessary measurement operation. In particular, power consumption of a wireless terminal device in the idle state can be reduced, resulting in remarkable effects.

(1-9) More preferably, the neighboring cell information generation unit generates initial neighboring cell information, based on a result of measurement in which a wireless terminal device communicating with the target wireless base station device has measured, in a plurality of frequencies, the reception levels of the radio signals transmitted from the wireless base station devices other than the target wireless base station device.

(1-10) More preferably, the neighboring cell processing device further includes a power measurement indication unit. In a case where the target wireless base station device operates in a hybrid mode in which the wireless terminal devices are registerable and both the registered wireless terminal devices and unregistered wireless terminal devices are allowed to access the target wireless base station device, the power measurement indication unit instructs the unregistered wireless terminal devices to measure, in the plurality of frequencies, the reception levels of the radio signals transmitted from the wireless base station devices other than the target wireless base station device.

This configuration prevents the power of a wireless terminal device owned by a registered user from being consumed, thereby providing appropriate communication services.

(1-11) More preferably, the neighboring cell processing device further includes a power measurement indication unit. In a case where the target wireless base station device operates in a hybrid mode in which the wireless terminal devices are registerable and both the registered wireless terminal devices and unregistered wireless terminal devices are allowed to access the target wireless base station device, the power measurement indication unit instructs the registered wireless terminal devices to measure, in the plurality of frequencies, the reception levels of the radio signals transmitted from the wireless base station device other than the target wireless base station device.

This configuration prevents the power of a wireless terminal device owned by an unregistered user who is usually not able to quickly charge the wireless terminal device from being consumed, thereby providing appropriate communication services.

(1-12) Preferably, in a case where the target wireless base station device operates in a hybrid mode in which the wireless terminal devices are registerable and both the registered wireless terminal devices and unregistered wireless terminal devices are allowed to access the target wireless base station device, the neighboring cell information generation unit weights the movement information of the registered wireless terminal devices and the movement information of the unregistered wireless terminal devices, and generates the neighboring cell information based on a result of the weighting.

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